<!DOCTYPE html>
<html>
  <head>
    <meta charset="UTF-8" />
    <title>3.表单</title>
  </head>
  <body>
    <form action="https://www.baidu.com">
      用户名：<input type="text" name="username"> <br><br>
      <button>点我1</button>
      <button>点我2</button>
      <button>点我3</button>
      <input type="submit" value="确认">
    </form>
  </body>
</html>